New Zealand orders top-level inquiry into Christchurch attacks

New Zealand's Prime Minister Jacinda Ardern has ordered an independent judicial inquiry into the Christchurch mosque attacks that left 50 people dead.

Speaking to the media, the leader said a royal commission would examine whether police and intelligence services could have done more to prevent the March 15 massacre.

"It is important that no stone is left unturned to get to how this act of terrorism occurred and how we could have stopped it," she told reporters.

"One question we need to answer is whether or not we could or should have known more."

Earlier, Ardern ruled out re-introducing the death penalty for the trial.